Package gavo :: Package protocols :: Module uws :: Class BaseUWSJob

Class BaseUWSJob

object --+
         |
        BaseUWSJob

Known Subclasses:

UWSJobWithWD

An abstract UWS job.

UWS jobs are always instanciated with a row from the associated jobs table (i.e. a dictionary giving all the uws properties). You can read the properties as attributes. UWSJobs also keep a (weak) reference to the UWS that made them.

To alter uws properties, use the change method. This will fail unless the job was created giving writable=True.

To make it concrete, you need to define:

a _jobsTDid attribute giving the (cross) id of the UWS jobs table for this kind of job
a _transitions attribute giving a UWSTransitions instance that defines what to do on transistions
as needed, class methods _default_<parName> if you need to default job parameters in newly created jobs
as needed, methods _decode_<parName> and _encode_<parName> to bring uws parameters (i.e., everything that has a DB column) from and to the DB representation from python values.

You may want to override:

a class method getNewId(uws, writableConn) -> str, a method allocating a unique id for a new job and returning it. Beware of races here; if your allocation is through the database table, you'll have to lock it and write a preliminary record with your new id. The default implementation does this, but if you want something in the file system, you probably don't want to use that.
a method _setParamsFromDict(argDict), which takes a nevow-style request.args dictionary and sets the job parameters. This is only necessary if you need extra mappings between names and such.

For every piece of the job parameters, define class attributes _parameters_<parname.lower()> with JobParameter values saying how they are serialized and deserialized. Only parameters defined in this way are accepted and integrated into the parameters dict.

If you need to clean up before the job is torn down, redefine the prepareForDestruction method.

Nested Classes
	__metaclass__ The metaclass for UWS jobs.

Instance Methods

__init__(self, props, uws, writable=False)
x.__init__(...) initializes x; see help(type(x)) for signature

source code

__getattr__(self, name)

source code

__setattr__(self, name, value)
x.__setattr__('name', value) <==> x.name = value

source code

setSerializedPar(self, parName, parValue)
enters parName:parValue into self.parameters after deserializing it.

source code

setPar(self, parName, parValue)
enters parName:parValue into self.parameters.

source code

getSerializedPar(self, parName)
returns self.parameters[parName] in text form.

source code

iterSerializedPars(self)
iterates over the serialized versions of the parameters.

source code

iterParameterNames(self)
iterates over the names of the parameters declared for the job.

source code

setParamsFromRequest(self, request)
sets our parameter dict from a nevow request.

source code

getTransitionTo(self, newPhase)
returns the action prescribed to push self to newPhase.

source code

change(self, **kwargs)
changes the property values to what's given by the keyword arguments.

source code

getProperties(self)
returns the properties of the job as they are stored in the database.

source code

update(self)
fetches a new copy of the job props from the DB.

source code

prepareForDestruction(self)
is called before the job's database row is torn down.

source code

getURL(self)
returns the UWS URL for this job.

source code

getWritable(*args, **kwds)
a context manager for a writeable version of the job.

source code

Inherited from object: __delattr__, __format__, __getattribute__, __hash__, __new__, __reduce__, __reduce_ex__, __repr__, __sizeof__, __str__, __subclasshook__

Class Methods

getNewId(cls, uws, conn)

source code

getDefaults(cls, conn)
returns a dictionary suitable for inserting into a jobsTD table.

source code

Properties
	quote Always returns None.
Inherited from `object`: `__class__`

Method Details

init(self, props, uws, writable=False)
(Constructor)

source code

x.__init__(...) initializes x; see help(type(x)) for signature

Overrides: object.__init__: (inherited documentation)

setattr(self, name, value)

source code

x.__setattr__('name', value) <==> x.name = value

Overrides: object.__setattr__: (inherited documentation)

setSerializedPar(self, parName, parValue)

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enters parName:parValue into self.parameters after deserializing it.

This is when input comes from text; use setPar for values already parsed.

getSerializedPar(self, parName)

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returns self.parameters[parName] in text form.

This is for use from a text-based interface. Workers read from parameters directly.

setParamsFromRequest(self, request)

source code

sets our parameter dict from a nevow request.

This can be called on both writable and non-writable jobs.

getTransitionTo(self, newPhase)

source code

returns the action prescribed to push self to newPhase.

A ValidationError is raised if no such transition is defined.

change(self, **kwargs)

source code

changes the property values to what's given by the keyword arguments.

It is an AttributeError to try and change a property that is not defined.

getProperties(self)

source code

returns the properties of the job as they are stored in the database.

Use attribute access to read them and change to change them. Do not get values from the dictionary you get and do not change the dictionary.

update(self)

source code

fetches a new copy of the job props from the DB.

You should in general not need this, since UWSJob objects are intended to be short-lived ("for the duration of an async request"). Still, for testing and similar, it's convenient to be able to update a UWS job from the database.

prepareForDestruction(self)

source code

is called before the job's database row is torn down.

Self is writable at this point.

getWritable(*args, **kwds)

source code

a context manager for a writeable version of the job.

Changes will be written back at the end, and the job object itself will be updated from the database.

If self already is writable, it is returned unchanged, and changes are only persisted when the enclosing controlling block finishes.

Decorators:

@contextlib.contextmanager

Property Details

quote

Always returns None.

Override if you have a queue management.

Get Method:: unreachable.quote(self) - Always returns None.

Class BaseUWSJob

__init__(self, props, uws, writable=False) (Constructor)

__setattr__(self, name, value)

setSerializedPar(self, parName, parValue)

getSerializedPar(self, parName)

setParamsFromRequest(self, request)

getTransitionTo(self, newPhase)

change(self, **kwargs)

getProperties(self)

update(self)

prepareForDestruction(self)

getWritable(*args, **kwds)

quote

init(self, props, uws, writable=False)
(Constructor)

setattr(self, name, value)